Originally Posted by Artemis
I'm sorry but to much is wrong here! Fancies WILL DIE in water to hot, 65-75 with 68 is preferred temps. Reduce feeding at 60 and stop when temps hit about 30. Commons do FINE in indoor aquariums. 20 gal for the first common, 10 after that, 10 per fancy.
Wow... Then my fancies should have been long dead by now. They've been in 76F water for months now. Pretty sure Olimpia keeps hers around 78F. No problems from either of our tanks. Goldfish are much more temp-tolerant than most people think. Fishbase.org lists goldfish as being able to tolerate up to 104.5F temps
. And many do fine in full sun ponds that get above 80F in the summer.
I would never feed my fish down to 30F. Almost all sources for pond fish recommend stopping feeding between 55F and 50F. Below those temps the GI tract doesn't work fast enough to digest all of that food before it begins to decay. This can and does cause fish to die.
I don't think a 12 inch fish would be very happy in a 55 or even 75 gal tank. Those tanks are only a few inches wider than the fish is long. Unless you're willing to custom-build something wide enough or buy a 200+ gal tank then I don't think you could provide a good PERMANENT indoor home for common goldfish.
If you think what we have said is so wrong, please provide sources to back up what you are saying.